The relationship between a banker and a customer can take several forms depending on the type of account or transaction. The main relationships include: 1. Creditor-debtor, with the customer as creditor and banker as debtor for deposit accounts. 2. Debtor-creditor, with the roles reversed for loan accounts where the customer is the debtor. 3. Trustee-beneficiary for safe deposit accounts, where the banker acts as trustee for items kept for safekeeping. The banker also has obligations to maintain customer confidentiality and honor checks properly presented, while customers must abide by terms of accounts like joint accounts.